<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="app">
        <button @click="doit">修改状态</button>
        <p v-if="true">第一个标签</p>
        <p v-if="isshow">第二个标签</p>
        <p v-if="temperature>=35">热</p>
    </div>

    <script src="./vue.js"></script>
    <script>
        var app = new Vue({
            el: "#app",
            data: {
                isshow: true,
                temperature: 40
            },
            methods: {
                doit: function() {
                    this.isshow = !this.isshow;
                }
            }

        })
    </script>

</body>

</html>